The recent stream of telecommunication has led to IP (Internet Protocol) standardization on audio communication systems representative of telephone networks. The 3GPP (3rd Generation Partnership Project), which is the working group on the standardization of mobile communications, drafted the specification for the standardization of the IP multimedia subsystem (IMS) serving as the platform for providing multimedia services such as audio services on the IP network. Recently, assessments have been carried out with respect to the fixed-type IP standardization on the next generation network (NGN).
Electronic mailing services have suffered from social problems such as Spam and unsolicited (or junk) mails, which are unwanted mails unilaterally sent to recipients by senders. Unsolicited communications occur due to various factors derived from the popularization of the Internet, such as significant decreases of communication costs and advanced capabilities of network access terminals (such as personal computers purchasable by common users) transmitting numerous electronic mails to unspecified persons or sites.
The above problem (already occurring in electronic mailing services) seems to occur in the IMS due to its popularization. The 3GPP specification has initiated the protection against unsolicited communication for EMS (simply referred to as “PUCI”) to protect users from Spam over the IP telephony (SPIT). In this connection, Patent Document 1 discloses a mobile network system having IMS entities.
Patent Document 1: Japanese Patent Application Publication No. 2007-527633
The 3GPP just started the assessment on the PUCI for the IMS. Subscriber originating calls are each subjected to testing by way of PUCI applications, which in turn evaluate calls with unsolicited rating scores. Unsolicited calls are rejected (or declined) but calls which are not regarded as unsolicited calls are forwarded to the user equipment. Herein, the problem is how the IMS involves the PUCI application for checking scores.